This invention relates to shell and tube heat exchangers.
All shell and tube heat exchangers include a shell and a bundle of tubes extending between opposing tubesheets. Heat is exchanged between a shellside fluid flowing through the shell and tubeside fluid flowing through the tubes.
A very desirable feature frequently employed in shell and tube heat exchangers is the annular distributor. Annular distributors can reduce shellside inlet and outlet pressure losses, reduce impingement velocities, and improve shellside fluid distribution. An annular chamber defined in the annular distributor is most conventionally in fluid communication with the shell interior through circumferentially spaced apertures in the shell wall.
Another feature common in shell and tube heat exchangers is a baffle cage. A baffle cage, as positioned in the shell, assists in support of the tubes within the shell and minimizes vibration and movement of the tubes. The baffle cage typically comprises longitudinally spaced baffles and longitudinally extending tie bars that interconnect the baffles. Preferably, the tie bars are connected at one end to one tubesheet, but are spaced from and left unconnected to the other tubesheet to allow for thermal expansion and contraction. If the tie bars were connected to both tubesheets, thermal expansion or contraction of the tie bars could cause longitudinal pressure upon the tubesheets and consequent loosening of the connection between the tubes and tubesheets. This effect exists even if one of the tubesheets is a "floating" tubesheet, since the tubes and tie bars expand and contract differently because of different temperatures and typically different materials.